I'm going to have to go with Bedok Jetty, looking at the number of big cobias landed there by Shore Angler. You can check out his website here. The jetty is rather competitive though, there will be a bunch of regulars taking up the good spots.

Cable car rig with live tamban is a good way to target for cobias along with other pelagic fishes. The alternative is the long trace bottom rig, but I'd prefer the former for Cobia.

Not that I am aware of. In my opinion, Labrador Jetty is not as good for pelagic fishes compared to Bedok Jetty due to current flow. Labrador Jetty used to get good current circulation before the Pasir Panjang Terminal land was reclaimed. The land reclamation effect is quite noticeable if you compare jigging for tambans with Bedok Jetty as well as Labrador jetty in the past. Less bait fish = less predatory fish.

So a days trip led to nothing but a big haul of tambans and another giant puffer
Another question though, how Long can tambans stay good in the freezer? I wrapped them in newspaper, hope to use them in the next few bookouts

Try not to overlap the tambans when you pack them, ie line them up nicely side by side, single layer. It makes it a lot easier to use when you're out fishing, just take out a few to thaw and the rest can still remain frozen in your ice box. In the freezer, you want to pack the tamban air tight the longer you want to keep them. This reduce freezer burn effect on the tambans. I personally find keeping them in the freezer for a few months very much usable if packed properly. 'Good' is subjective though.

It's very likely bioluminescence produced by Sea Pen when your tamban came into contact with it. I used to get them too while fishing at Punggol years back. I was quite baffled by it as well when my prawns came back glowing, till I got a Sea Pen on my hook along with the glowing substance.